Carter guested on Tuesday’s “Colbert Report” to promote his 28th book, “A Call to Action: Women, Religion, Violence and Power.” The liberal former Commander-in-Chief and the conservative Comedy Central character duked it out over a number of issues mentioned in the book’s subtitle.

Colbert said he wants to read Carter‘s book, but he doesn’t want to feel any additional guilt than what he already has. “I feel guilty about black people,” Colbert said. “I feel guilty about women now — a black woman walks in the room and I’ve got to leave.”

On that note, the topic sort of turned to institutionalized slavery.

“Slavery’s a worse problem now than it ever was in the 19th century,” Carter said, referring to the international sex trade.